Changeable lock

ABSTRACT

A CHANGEABLE LOCK FOR USE WITH A LEVER OR KNOB-OPERATED DOOR UTILIZING A COMPARING DEVICE WITH WHICH CHANGEABLE AND MATEABLE SLUGS AND KEYS ARE COMPARED. WHEN A COMPATIBLE SLUG AND KEY ARE SENSED, THE BOLT OF THE DOOR IS DISPLACED AS THE DOORKNOB IS TURNED BY A CAMMING DEVICE. THE LOCK MAY BE OPENED FROM THE INSIDE BY MOVING THE INTERIOR DOORKNOB WITHOUT COMPARING THE KEY AND SLUG.

Filed Feb. 23, 19.58

'PnowEN ET'AL 2 Sheets-Sheet 1 1l l ".1 4. .y

Il m! FIG.

INVENTORS PAUL D. OWEN CHARLES R.HILEMN JAMES C. VELVIN P. D. OWEN ETAI- Jan. 1:9, 1971 CHANGEABLE LOCK Filed Feb. 23, 196s 2 Sheets-Sheet 2 INVENTORS PAUL D. OWEN CHARLES R. HILEMN JAMES C. VELVIN United States Patent O 3,555,858 CHANGEABLE LOCK Paul D. Owen, 539 Highland Ave. 27403; Charles R.

Hilemn, 1302 New Garden Road 27410; and James Carroll Velvin, Jr., 604 Dogwood Lane 27410, all of Greensboro, N.C.

Filed Feb. 23, 1968, Ser. No. 707,602 Int. Cl. E051: 25/00, 29/00 U.S. Cl. 70--384 3 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND, BRIEF SUMMARY AND OBJECTIVES OF THE INVENTION Room security presents an acute problem in the motel, hotel and oice rental area since continuous turnover of tenants or occupants quite naturally results in the circulation of many duplicate keys to the same room. Ordinarily, changing or door lock is expensive and time-consuming. Because of the time and money involved, it is a procedure which cannot practicably be done at frequent intervals.

Numerous attempts have been made to solve this problem including the use of plural key doors and combination locks, however, even a resettable combination lock presents administrative problems since it is not practical to change or have changed the combination more often than every thirty to sixty days because of the manpower, expense and time involved.

To meet the security problem, the present invention has been developed. It embodies, in a lock structure, the principle of comparing the cut edges and hence, mateable characteristics of two components referred to subsequently as the key and slug. In forming a mateable key and slug, a piece of flat stock may be separated along a predetermined precisely defined line by a changeable cutting tool not a part of the present invention. The cut slug is then placed within the lock structure adjacent a comparing device so that an exteriorly introduced key may be compared with the slug by the comparing device to determine whether or not the precisely cut edges of the slug and key correspond to and are compatible with each other. A compatible slug and key will permit the door bolt to be displaced and the door to be unlocked by continued rotation of the doorknob. The described principle permits use of an infinitely large number of mateable keys and slugs for the same lock and accordingly allows the room lock to be changed through the provision of a new key and slug simultaneously with check-in or occupancy by a new guest or tenant. The key and slug may be produced from an inexpensive, easily separable material by a presettable die cutting device which may be installed in the hotel, motel or rental oliice. In the event the locks to be used are in a motel or hotel facility, the slug may be inserted on the interior side of the door by the bellboy or attendant at which time the previously used slug is removed. Thus the guests are permitted and even encouraged to retain the key as a souvenir or advertising reminder which was used during their occupancy of the room involved since there is almost no possibility that the key could be used subsequently to reopen the door of the same room.

3,555,858 Patented Jan. 19, 1971 rice The lock of the preesnt invention comprises broadly a boltwhich moves to unlock the door when displaced by a camming device directly responsive to the rotation of the exterior doorknob. The comparing mechanism which includes primarily a plurality of slotted plates slidably movable with respect to each other, permits displacement of the bolt by the camming device when reaching a selected position determined, for example, when a slug and key are compared, found to be cut apart from the same piece of material and thus found to be mateable or compatible along the cut edge of the material.

Accordingly, it is therefore one of the objects of the present invention to provide a lock of the type described which will be responsive to a large number of mateable and comparable components.

Another object of the present invention is'to provide a lock of the type described particularly useful in hotels, motels, ofce buildings, bus, train and airport lockers, post ofiice boxes, parking meters, and other related areas where the existence of duplicate keys create constant problems in the possession of dishonest people.

A further object of the present invention is to provide a comparing mechanism for a variable lock which will be responsive to an infinitely large number of differently contoured keys and slugs so that the lock may be reset at frequent intervals without the use of tools and the like.

Yet still another object of the present invention is to provide a variable lock of the type described wherein a new key and mating slug may be made by the attendant or rental agent and furnished to the guest or occupant at the time of occupancy.

Yet still another further object of the present invention is to provide a changeable lock of the type described which is at all times openable from the inside of the room without the use of a key but which may be only opened from the outside when a key is inserted, compared and found compatible with the previously installed slug.

Yet still another further object of the present invention is to provide a changeable lock of the type described wherein the occupant of a room is allowed and even encouraged to retain the key which may bear advertising or other valuable information while the proprietor is secure in his knowledge that the key can no longer be used to reopen the same room.,

These and other objects of the present invention will become more apparent after a consideration of the following detailed description taken in conjunction with the accompanying drawings wherein like characters of reference designate like parts throughout the several views.

FIGURE DESORIPTION FIG. 1 is a perspective and fragmentary view of the exterior of a door having an installed lock embodying the present invention showing the positioning of a key within the lock from the exterior of the door and a mateable slug from the interior of the door.

FIG. 2 is a perspective, fragmentary and isolated view of the bolt :and inside door operating mechanism securable to the interior doorknob so that the door may be opened anytime the knob is displaced.

FIG. 3 is a side elevational, fragmentary and isolated view of the displacement of the cam shown in FIG. 2 to move the bolt and unlock the door when the interior knob is displaced.

FIG. 4 is an exposed side elevational and sectional view of the interior of the changeable lock embodying the present invention showing the positioning of the key and mateable slug as well as the operation of the camming device to displace the bolt when the compared key and slug are compatible.

FIG. 5 is a plan view of the changeable look interior shown in FIG. 4 illustrating the location of the interior and exterior doorknobs in conjunction with the internal components of the lock.

FIG. 6 is a plan View of the comparing device comprised of a plurality of slidable and notched plates which respond to the cut edges of keys and slugs to form a continuous registered groove if the key and slug compared are cut from the same stock and are thus compatible.

FIG. 7 is an isolated side elevational view of a portion of the bolt and comparing device of a changeable lock embodying the present invention disclosing the manner in which the bolt is released by the camming device when the key and slug examined are compatible.

FIG. 8 is a perspective isolated view of the camming mechanism which displaces the bolt when a slug and key are compared and found compatible.

FIG. 9 is a perspective isolated view of a single notched plate a number of which make up the comparing device showing the leaf biasing springs on each end of the plate and the coil-sustaining spring attached to one plate end.

FIG. 10 is a perspective view of the comparator of the comparing device which is pivotally sustained and determines whether or not a continuous groove is formed within the tops of the notched slidable plates when a key and slug are compared.

FIG. ll is a perspective, isolated and exploded view of the slidable platform assembly which supports the slug, key and slidable notched plates and enables the comparison between key and slug to take place.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings and particularly to FIG. 1, a Changeable or variable lock assembly shown generally as is located in a conventional manner within the door structure and operated by interior and exterior doorknobs 22 and 24. A multiple bolt shown generally as 26 is used as a locking device so that the bolt must be withdrawn into the lock structure and away from the keeper (not shown) located in the jam for the door to open.

Initially it is to be noted that the lock of the present invention may be, though this is not an express requirement, operated from the interior of the door without the use of a key. That operation is best illustrated in PIG. 2 wherein a securing ring 26 fastens directly to the interior doorknob 22 and is secured against a bell crank member 28 from which extends a shaft 30 that will displace a shaft 32 against a linkage 34 (see FIG. 3). Linkage 34 has an extruding pin 36 that will contact lug 38 formed along the lower bolt 40 to displace that bolt rearwardly (see arrow) when the interior knob 22 is rotated in a clockwise direction. A bearing 42 secured to bell crank 28 is continuously biased by spring 44 in a rearward direction, the spring being strong enough to cause a displacement of linkage 34 and bolt 40 upon the initial rotation of the knob and the subsequent movement of bell crank 28. Continued rotation of the knob will eventually override the biasing of spring 44 and cause the bearing 42 to slide on shaft 32 and assume the position shown in FIG. 3. Thus rotation of the interior doorknob 22 will always withdraw the bolt and unlock the door even when no key is used.

Within the housing 20 a substantially horizontal shelf 46 spans the side walls 48 and 49 of the housing to form a platform to sustain a slug 50 and a key 52 to be compared. A side plate 54 holds the components in a reasonably secure position and avoids any misalignment of the components during movement of the door.

The shelf cooperates with a slidably contiguous rnember 56 best illustrated in FIG. l1, that member having an upwardly extending key 58 cooperating with a slot 60 in the shelf 46 to make possible the comparison of the key with ,the slug. A bearing block 62 retains the mem- Cit ber 56 in continuous slidable contact with the shelf 46.

The comparing mechanism shown generally as 64 includes a plurality of slotted plates 6'6, one of which is shown in detail in FIG. 9, which creates an aligned groove 618 when a compatible slug 50 and key 52 are compared. The numerous slots or grooves in each of the plates 66 may be of varying width so that any number of combinations may be -rnade available so long as the key and slugs are cut from the same piece of material along a common line and will thus be recombinable during the comparing operation.

A key and slug cutting device embodying similarly constructed and arranged slotted plates 66 is used to form the mating keys and slugs from a single piece of flat stock and can be positioned in a rental office so that the occupant or tenant may be furnished the key immediately upon taking possession of the premises. It has been found advantageous to provide a counter with the :key and slug making apparatus so that every combination of slots or grooves used may be made of record. This is especially important since the tenant or room occupant might misplace the assigned key and thus be required to obtain a new key from the rental oflice. It would, in fact, be advantageous to make at least one additional key at the time the premises are occupied so that the management or proprietor will have another existing key which can be selectively furnished to the maids for room cleaning or used in the event other emergency situations arise.

The comparing operation involves the use of a comparator 70 (see FIG. 10) which can sense a continuous opening or groove 68 formed by the slots atop the movable plates when a compatible slug and key are compared. The large bolt 72 carries a continuously biased latch 74 which engages the front portion 76 of the comparator 70 so long as the sensor 78 of the comparator does not extend inwardly into a formed continuous groove 68. Once a groove is formed, the lower edge 80 of the sensor 78 extends therein thus lowering the comparator about pivot point 82 and disengaging the upper end 76 from the latch 74.

A spring 84 continuously biases the comparator upwardly until the camming edge 86 of the camming mechanism 88 urges the comparator 70 downwardly about pivot point 82 in a manner to be described in greater detail subsequently.

The camming mechanism 88 is controlled by rotation or movement of the exterior doorknob 24 which is connected directly to shaft 90. The rotation of shaft 90 when the doorknob is turned will swing the cam 92 in a clockwise direction (see arrow) to force the camming edge 86 against the comparator 70 as previously described. Additionally, a pawl 94, secured to the shaft 90, will, upon rotation of that shaft, eventually contact a pawl-engaging stop 96 formed within the structure of the large bolt 72. Continued rotation of shaft 90 by movement of the doorknob then forces the large bolt to the right as viewing FIG. 4 which will withdraw the bolt from the cooperating keeper (not shown) located in the adjacent door jam.

In the event the interior knob is turned, the smaller bolt 40 moves to the right as viewed in FIG. 4 and a rider wheel 98 then rides against the contoured lower edge 100 of latch 74 to raise that latch and disengage it from the forward edge 76 of the comparator 70. This operation will allow the entire bolt assembly to move to the right as viewing FIG. 4 as the knob continues to turn since the pawl 94 will again engage the stop 96 to displace the large bolt assembly. Thus the disengagement of the latch 74 with the comparators forward edge 76 permits, in each instance, the unlocking of the door whether it be done by the comparing operation wherein the comparator 70 moves downwardly about pivot point 82 and into a formed aligned groove 68 in the notched plates or whether the smaller bolt 40 which is displaced when the interior doorknob moves the latch 74 upwardly.

A large coiled spring 102 continually biases the bolt assembly 25 to the left as viewing FIG. 4 so that the large bolt is kept within the cooperating keeper and the door maintained in a locked condition. An elongated finger 104 is pivotally secured to cam 92 and extends downwardly through a slot 106 formed within the member 56 to move the member 56 to the left as viewing FIG. 4 and cause the comparison between the slug and the key 52.

to take place. A strong coil spring 108 keeps the finger 104 relatively rigid with respect to the cam 92 during the comparing operation and only allows the finger 104 to move relative to the cam 92 after the comparing operation has taken place and the member 56 has been displaced as far as necessary to compare slug with key. The spring 108 will allow the cam 92 to continue to rotate as the exterior doorknob is turned so that some override is provided for the comparing device to the extent necessary in retracting the large bolt 72 from its cooperating keeper (not shown).

The slug is extended into the housing 20 from the inside of the door through a convenient slot, and any number of techniques are available for temporarily sealing that slug within the housing so that it will not become dislodged or misaligned within the lock structure as the door is slammed or jolted. The slug will be positioned along the shelf 46 as shown in exploded FIG. 1l, and it is contemplated that management or room service will be the usual operating medium for placing the slug within the lock housing for each new occupant. The key 52 will be inserted through a slot 110 in the front of the door by the tenant or room occupant. Conceivably, the key might be positioned in a movable plate first in a vertical position and then rotated 90 degrees to assume a horizontal position atop the shelf 46. While any number of variations are possible in this arrangement, it is only necessary eventually to place the slug and key flat within the same plane so that the comparing operation may take place as illustrated in FIGS. 6 and ll.

Each of the slotted plates 66 are constructed as shown in FIG. 9, i.e., they each contain a coil spring 112 secured to one end and extending to the wall 49 of the housing. This insures that the plate 66 will be pulled suiciently against wall 49 (to the right as viewing FIG. 4) to permit easy insertion and withdrawal of the slug 50 on the opposite end of the shelf 46. As the finger 104 moves member 56 and thus urges the plate 56 against the cut edge of slug 50, the springs 112 are tensioned and respond immediately when the doorknob is released to return the plates 66 back toward wall 49 and away from the cut edge of the sliug 50. Each plate has a leaf spring 114 affixed to both ends to insure that the particular plate has no slack if it is spaced between non-compatible components where a void or recess might not otherwise be detected. While both leaf springs 114 provide added insurance that the plate will be perfectly aligned, it is possible that only one would be required, for example, along the cut edge of the key to make certain that no voids remain and improper fittings occur.

Thus it can be seen and understood that the changeable lock of the present invention makes possible the use of an infinite number of mateable components which, when compatibly mated, form an aligned recess that will receive the sensor of a comparator and thus allow that comparator to pivot downwardly away from a retaining latch secured to the lock bolt. The withdrawal of this sensor edge from the latch allows the continued rotation of the doorknob to urge the lbolt out of the keeper and back into the lock housing, an operation which unlocks the door. It will be apparent that an infinitely large number of combinations are available by using the grooved plates shown in FIG. 6 since it is only necessary to form one aligned groove 68 somewhere within the upper edges of the plate to receive the sensor of the comparator. The workable combinations can be expanded significantly by reversing one or more of the plates physically within the mast to thus reorient the Varying plate grooves.

While there has been described one preferred embodiment of a changeable lock using a comparing mechanism for releasing the lock, it will be readily apparent to those skilled in the art that variations and alterations may be made in the camming device, the comparing apparatus, the bolt structure and other facets of the inventive concept without departing from the real spirit and purpose of the invention. Such modifications and changes as well as the use of mechanical equivalents are contemplated.

We claim:

I1. A changeable lock for use with an interior and exterior knob-operated door comprising; a shaft; a bolt; camming means responsive to movement of said shaft; comparing means displacea'ble by said camming means; changeable and mateable components cooperating with said camming means to position said comparing means to a selected location; said camming means permitting displacement of said bolt to unlock the door upon registry of said camming means with said comparing means in a pre-selected position; said comparing means including a plurality of slotted plates slidably movable by said camming means to compare said changeable and mateable components; said changeable and mateable components including a mateable key and slug; said slug being removably positioned proximate said comparing means from the interior of the door and said key being removably positioned proximate said comparing means from the exterior of the door; said camming means including a rotatable cam responsive to the rotation of the exterior knob and a spring biased finger secured to said cam displacing said slotted plates to compare said slug and said key.

2. A lock as claimed in claim 1 wherein movement of the interior doorknob displaces said bolt and unlocks the door.

3. A lock as claimed in claim 2, said bolt having a pawl-engaging stop and a sensor-release member, 4said camming means further comprising a sensor movable into and out of alignable slots within said plates by said rotatable cam, said member comprising a pawl movable with said cam to the extent that the bolt is displaced by movement of the exterior knob when the pawl engages the stop and the sensor moves into the plate-aligned slots and away from the sensor-release member.

References Cited UNITED STATES PATENTS 1,948,174 2/ 1934 Haviland 70-383 2,692,495 10/ 1954 Verdon 70-35l 2,970,466 2/ 1961 Wellekens 70-339 3,167,944 2/1965 Pickering 70-382 FOREIGN PATENTS 692,736 6/ 1953 Great Britain 70-385 MARVIN A. CHAMPION, Primary Examiner ROBERT L. WOLFE, Assistant Examiner U.S. Cl. X.R. 70-352 

